Method for altering locations of survey measurements along a borehole so as to increase measurement density

ABSTRACT

A method may include providing a drill string including a measurement tool. The drill string may be positioned in a wellbore. The method may include taking a measurement with the measurement tool at a first location. The method may include coupling a pipe stand including a first selected number of tubular segments to the drill string, the first selected number being two or more. The method may include lowering or advancing the drill string into the wellbore the length of the pipe stand. The method may include taking a measurement with the measurement tool at a second location. The method may include raising the drill string the length of a tubular segment. The method may include removing a second selected number of tubular segments from the drill string, the second selected number different from the first selected number. The method may include taking a measurement with the measurement tool at a third location. The method may include raising the drill string the length of the first selected number of tubular segments. The method may include removing the first selected number of tubular segments. The method may include taking a measurement with the measurement tool at a fourth location.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application which claims priorityfrom U.S. utility application Ser. No. 15/476,107, filed Mar. 31, 2017,which is a nonprovisional application which claims priority from U.S.provisional application No. 62/316,411, filed Mar. 31, 2016.

TECHNICAL FIELD/FIELD OF THE DISCLOSURE

The present disclosure relates generally to downhole measurement tools,and specifically to methods of operating downhole measurement tools.

BACKGROUND OF THE DISCLOSURE

Knowledge of wellbore placement and surveying is useful for thedevelopment of subsurface oil & gas deposits, mining, and geothermalenergy development. Accurate knowledge of the position of a wellbore ata measured depth, including inclination and azimuth, may be used toattain the geometric target location of, for example, an oil bearingformation of interest. Additionally, accurate relative placement of awellbore to a geological zone or formation, or relative to one or moreadjacent wellbores, may be useful for the production or hydrocarbons orgeothermal energy. Additionally, knowledge of the formation propertiessurrounding a wellbore along its depth may be used to guide wellboreplacement into desired geological features or zones. Traditionally acombination of sensors are deployed on a drill string to measure theseproperties.

The measurement of inclination and azimuth of the wellbore may be usedin surveying operations. Inclination is the angle between thelongitudinal axis of a wellbore or a drill string or other downhole toolpositioned in a wellbore and the Earth's gravity vector, and azimuth isthe angle between a horizontal projection of the longitudinal axis andnorth, whether measured by a magnetometer (magnetic north) or by a gyro(true north). In some instances, surveying operations may includeestimating the distance, orientation, or both the distance andorientation of a borehole relative to other boreholes by measuring themagnetic field that is produced either passively from the adjacentwellbore's casing or drill pipe, or by measuring an actively generatedmagnetic field.

One method of determining the orientation and position of a downholetool with respect to the Earth spin vector is to take a gyro survey,referred to herein as a gyrocompass, to determine a gyro toolface,inclination, and azimuth. The gyrocompass utilizes one or moregyroscopic sensors, referred to herein as gyros to detect the Earth'srotation and determine the direction to true north from the downholetool, the reference direction for a gyro toolface and azimuth.

The determination of orientation, position, inclination, and azimuth ofthe downhole tool may include determining a gravity toolface or magnetictoolface by using one or more accelerometers or magnetometersrespectively. Accelerometers may be used to detect the local gravityfield, typically dominated by the Earth's gravity, to determine thedirection to the center of the Earth. This direction may be used as thereference direction for a gravity toolface. Magnetometers may similarlybe used to detect the local magnetic field, typically dominated by theEarth's magnetic field, to determine the direction to magnetic north.This direction may be used as the reference direction for a magnetictoolface.

These measurements, referred to herein as a survey, may be taken by asurveying tool positioned on a drill string. A drill string is typicallymade up of tubular segments joined end to end, which are built up orbroken down on a drilling rig to increase or decrease respectively theoverall length of the drill string during the drilling or completionsprocess. Typically, tubular segments are joined in sections of two orthree before being added to the drill string, or are removed in sets oftwo or three, referred to herein as a pipe stand. While the pipe standis joined to or removed from the drill string, the drill stringcontaining the survey or LWD tool may typically be held relativelystationary. These conditions during the joining and removal process maybe ideal for making survey or logging while drilling (LWD) measurements.

SUMMARY

The present disclosure provides for a method. The method may includeproviding a drill string including a measurement tool. The drill stringmay be positioned in a wellbore. The method may include taking ameasurement with the measurement tool at a first location. The methodmay include coupling a pipe stand including a first selected number oftubular segments to the drill string, the first selected number beingtwo or more. The method may include lowering or advancing the drillstring into the wellbore the length of the pipe stand. The method mayinclude taking a measurement with the measurement tool at a secondlocation. The method may include raising the drill string the length ofa tubular segment. The method may include removing a second selectednumber of tubular segments from the drill string, the second selectednumber different from the first selected number. The method may includetaking a measurement with the measurement tool at a third location. Themethod may include raising the drill string the length of the firstselected number of tubular segments. The method may include removing thefirst selected number of tubular segments. The method may include takinga measurement with the measurement tool at a fourth location.

The present disclosure also provides for a method. The method mayinclude providing a drill string. The drill string may include ameasurement tool. The drill string may be positioned in a wellbore. Themethod may include taking a measurement of the wellbore with themeasurement tool at a first location. The method may include removing apipe stand including a first selected number of tubular segments fromthe drill string, the first selected number being two or more. Themethod may include raising the drill string the length of the pipestand. The method may include taking a measurement of the wellbore withthe measurement tool at a second location. The method may include addinga second selected number of tubular segments to the drill string, thesecond selected number different from the first selected number. Themethod may include lowering the drill string the length of the secondselected number of tubular segments. The method may include taking ameasurement of the wellbore with the measurement tool at a thirdlocation. The method may include adding a pipe stand to the drillstring, the pipe stand including the first selected number of tubularsegments. The method may include lowering the drill string the length ofthe pipe stand. The method may include taking a measurement of thewellbore with the measurement tool at a fourth location.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of the variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 depicts a portion of a measurement operation consistent with atleast one embodiment of the present disclosure.

FIG. 2 depicts a portion of a measurement operation consistent with atleast one embodiment of the present disclosure.

FIG. 3 depicts a portion of a measurement operation consistent with atleast one embodiment of the present disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various embodiments. Specific examples of components and arrangementsare described below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

As depicted in FIG. 1, drill string 100 may be positioned in wellbore10. Wellbore 10 may extend into Earth 15 from surface 20. Drill string100 may be manipulated by drilling rig 25, which may have apparatuses torotate drill string 100 as wellbore 10 is formed in Earth 15. In certainembodiments, drilling rig 25 may be a workover rig. In some embodiments,drilling rig 25 may include hoisting apparatuses such as drawworks 30and traveling block 35.

In some embodiments, drill string 100 may include measurement tool 101.Measurement tool 101 may be a survey tool or any measurement whiledrilling (MWD) or logging while drilling tool (LWD). Example LWD toolsmay include, but are not limited, to resistivity, porosity, naturalgamma detectors, spectral gamma detectors, and borehole calipers.Example MWD tools may include sensors that measure the earth'sinclination and azimuth, such as survey tools.

Measurement tool 101 may include one or more sensors such as, forexample and without limitation, magnetometers, accelerometers, or gyros.Measurement tool 101 may, for example and without limitation, be used tomake measurements within wellbore 10 as drill string 100 is insertedinto or removed from wellbore 10. Although depicted as being at an endof drill string 100, one having ordinary skill in the art with thebenefit of this disclosure will understand that measurement tool 101 maybe positioned at any point along drill string 100 without deviating fromthe scope of this disclosure.

As understood in the art, drill string 100 may be formed from aplurality of tubular segments 103 joined end to end. In someembodiments, tubular segments 103 may be sequentially added to drillstring 100 as wellbore 10 is drilled or as drill string 100 is made upinto wellbore 10. In some embodiments, drill string 100 may thus be madeup by lowering drill string 100 into wellbore 10 and adding one or moretubular segments 103 to drill string 100 with drilling rig 25. Thelowering and adding operations may be repeated until drill string 100has extended a desired length into wellbore 10. In some embodiments, afirst preselected number of previously joined tubular segments 103,depicted in FIG. 1 as pipe stands 105 including three tubular segments103, may be added to drill string 100 at each step. Pipe stands 105 maybe made up prior to forming drill string 100. The first preselectednumber of tubular segments 103 may be any number, two or more, oftubular segments 103 capable of being handled by drilling rig 25 asunderstood in the art.

In some embodiments, as drill string 100 is tripped or lowered into thewellbore 10 or as the wellbore 10 advances due to the drilling process,measurement tool 101 may be used to take a measurement of wellbore 10during the time in which drill string 100 is stopped as the next pipestand 105 is added. Measurements may thus be taken at a first set ofmeasurement locations 107 as depicted in FIGS. 1-3 as drill string 100is inserted into wellbore 10. Thus, for example and without limitation,in an embodiment in which pipe stands 105 consist of multiples of threetubular segments 103, measurement locations 107 may be evenly spaced inwellbore 10 at a distance corresponding to the length of three tubularsegments 103.

In some embodiments, drill string 100 may be tripped out of wellbore 10by raising drill string 100 by drilling rig 25 and removing one or moretubular segments 103 from drill string 100 at drilling rig 25. In someembodiments, during the tripping out operation, a second preselectednumber of tubular segments 103 may be removed from drill string 100different from the first preselected number of tubular segments 103which were added to make up drill string 100. The second preselectednumber of tubular segments 103 may be any number of tubular segments 103which is different from the first preselected number of tubular segments103. For example and without limitation, as depicted in FIG. 2, a singletubular segment 103′ may be removed from drill string 100. Subsequently,a measurement may be taken with measurement tool 101 at modifiedmeasurement location 109. In other embodiments, as understood in theart, two tubular segments 103 may be removed without deviating from thescope of this disclosure in a case where pipe stands 105 are threetubular segments 103 in length.

Drill string 100 may then be tripped out of wellbore 10 by raising drillstring 100 by drilling rig 25 and removing tubular segments 103 as pipestands 105′ having the first preselected number of tubular segments 103as depicted in FIG. 3. Measurement tool 101 may be used to take ameasurement of wellbore 10 during the time in which each pipe stand 105′is removed from drill string 100. Measurements may thus be taken at asecond set of measurement locations 107′ as depicted in FIG. 3.Measurement locations 107′ may thus be evenly spaced in wellbore 10 at adistance corresponding to the length of pipe stand 105′. Measurementlocations 107′ may thus be offset from measurement locations 107 by thelength of the second preselected number of tubular segments 103′ removedfrom drill string 100. In an embodiment in which one tubular segment103′ is removed as depicted in FIG. 2, measurement locations 107′ may beoffset from measurement locations 107 by the length of one tubularsegment 103′. Thus, this method may be utilized to increase measurementdensity along the length of a wellbore.

Measurements taken by measurement tool 101 at measurement locations 107and measurement locations 107′ may be utilized to generate a model ofwellbore 10. Measurements taken by measurement tool 101 at measurementlocations 107 and 107′ may be combined with other measurement or LWDinformation measured during drilling, such as continuous inclination andazimuth surveys, to generate a model of wellbore 10.

In some embodiments, instead of removing a second preselected number oftubular segments 103′, the second preselected number of tubular segments103′ may be added prior to the tripping out operation. In someembodiments, the second preselected number of tubular segments 103′ maybe added or removed from drill string 100 before a tripping inoperation. Although described as a tripping out and tripping inoperation, one having ordinary skill in the art with the benefit of thisdisclosure will understand that the measurement operations describedherein may be applied to a tripping in and tripping out operationwithout deviating from the scope of this disclosure. One having ordinaryskill in the art with the benefit of this disclosure will understandthat one need not measure during a trip in before measurement during atripping out operation.

In some embodiments, a third preselected number of tubular segments 103may be added to or removed from drill string 100 before a tripping inoperation as described with respect to FIG. 1 subsequent to the trippingout operation described with respect to FIG. 3. In such an embodiment,for example and without limitation, the first preselected number oftubular segments 103 used to form pipe stands 105 may be three, thesecond preselected number of tubular segments 103 added to or removedfrom drill string 100 may be one, and the third number of tubularsegments 103 added to or removed from drill string 100 before the nexttrip in may be one or two. In an example in which each tubular segment103 is 30 feet long, the first tripping in operation may result inmeasurement locations 107 being taken 90 feet apart, the tripping outoperation may result in measurement locations 107′ being spaced 90 feetapart, offset 30 feet from measurement locations 107, and the subsequenttripping in operation (not shown), may result in measurement locationsbeing spaced 90 feet apart, offset 30 feet from measurement locations107 and 107′.

By taking measurements as discussed herein, measurements may be taken atmore measurement locations 107, 107′ and 109 along wellbore 10 than iftaken only at the first preselected length of pipe stand 105. Byincreasing the number of measurement locations 107, 107′, the datadensity of the measurements taken along wellbore 10, i.e. the number ofmeasurements taken per length of wellbore 10, may be increased. Theadditional data density may, for example and without limitation, reduceerror introduced when applying a curve-fitting algorithm or mathematicalmodels such as minimum curvature or spline fits to determine the spatialmodel of wellbore 10 from the measurement points.

In some embodiments, additional measurement tools (not shown) may bepositioned on drill string 100. In some such embodiments, the additionalmeasurement tools may be positioned spaced apart from measurement tool101 a distance other than the first predetermined length of pipe stand105 or the second predetermined length of tubular segment 103′. In somesuch embodiments, the additional measurement tools may provideadditional measurement locations along wellbore 10 other thanmeasurement locations 107, 107′, thus further increasing the datadensity gathered as discussed herein above. As described above, themeasurement information may be utilized to generate a model of awellbore 10.

In some embodiments, measurements taken during the surveys may be storedto internal memory positioned in measurement tool 101. In someembodiments, measurements taken during the measurement operations may betransmitted to a receiver (not shown) at surface 20. In some suchembodiments, measurements taken during the measurement operations may betransmitted by any suitable method known in the art including, forexample and without limitation, by wireline, MWD telemetry,electromagnetic telemetry, or mud pulse telemetry.

The foregoing outlines features of several embodiments so that a personof ordinary skill in the art may better understand the aspects of thepresent disclosure. Such features may be replaced by any one of numerousequivalent alternatives, only some of which are disclosed herein. One ofordinary skill in the art should appreciate that they may readily usethe present disclosure as a basis for designing or modifying otherprocesses and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein. Oneof ordinary skill in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

The invention claimed is:
 1. A method for measuring a wellbore, themethod comprising: (a) providing a drill string, a measurement toolcoupled to the drill string, and a plurality of pipe stands, each pipestand forming part of the drillstring or configured to be added to thedrill string, wherein each pipe stand comprises a first number oftubular segments, and wherein the pipe stands have a pipe stand length;(b) obtaining a first set of measurements from the measurement toolusing a first acquisition method along the wellbore at a first set offirst measurement locations that are spaced along the wellbore, whereinthe first measurement locations are separated by the pipe stand length,the first acquisition method comprising obtaining the first set ofmeasurements: i. during drilling as each pipe stand is added to thedrill string; ii. when tripping into the wellbore as each pipe stand isadded to the drill string; or iii. when tripping out of a wellbore aseach pipe stand is removed from the drill string; (c) following step(b), adding or removing a second number of tubular segments from thedrill string, wherein the second number of tubular segments is less thanthe first number of tubular segments; and (d) following step (c),obtaining a second set of measurements from the measurement tool using asecond acquisition method along the wellbore at a second set of secondmeasurement locations that are spaced along the wellbore, wherein thesecond measurement locations are separated by the pipe stand length, thesecond acquisition method comprising obtaining the second set ofmeasurements when: iv. tripping into the wellbore as each pipe stand isadded to the drill string; or v. tripping out of a wellbore as each pipestand is removed from the drill string; wherein the second set ofmeasurements is obtained during a tripping operation that is separatefrom the drilling or tripping operation during which the first set ofmeasurements is obtained.
 2. The method according to claim 1 wherein thepipe stand consists of between two and four tubular segments.
 3. Themethod according to claim 1 wherein the first set of measurements andthe second set of measurements are made with the measurement tool thatis a survey tool, a measurement while drilling (MWD) tool or a loggingwhile drilling tool (LWD).
 4. The method according to claim 3, whereinthe LWD tool is a resistivity tool, porosity tool, natural gammadetector, spectral gamma detector, or borehole calipers.
 5. The methodaccording to claim 3, wherein the MWD tool includes sensors that measurethe inclination/or azimuth of the wellbore.
 6. The method according toclaim 3, wherein the measurement tool includes magnetometers,accelerometers, or gyros, and wherein the magnetometers, accelerometers,or gyros are used to obtain the first and second sets of measurements.7. The method according to claim 6 wherein obtaining the first andsecond sets of measurements comprise determining orientation andposition of the tool with respect to Earth by taking a gyrocompass ormagnetic survey measurement.
 8. The method according to claim 1, furtherincluding a step of transmitting the measurements to a surface of Earthusing a method selected from the group consisting of wireline, MWDtelemetry, electromagnetic telemetry, and mud pulse telemetry.
 9. Themethod of claim 1, wherein the first acquisition method comprisesobtaining the first of measurements during drilling and the secondacquisition method comprises obtaining the second set of measurementswhen tripping out of a wellbore.
 10. The method of claim 1, wherein thefirst set of measurements and the second set of measurements are storedin a memory of the measurement tool.
 11. The method of claim 1, whereineach pipe stand comprises three tubular segments.
 12. The method ofclaim 1, wherein each measurement of the first and second sets ofmeasurements is performed when the drill string is stopped.
 13. Themethod of claim 12, wherein each measurement of the first and secondsets of measurements is performed when a stand of pipe is added orremoved.
 14. The method of claim 1, wherein in step (c), one or twotubular segments are added or removed from the drill string.
 15. Themethod of claim 1, wherein in step (d) the second acquisition method isdifferent from first acquisition method.
 16. The method of claim 1,wherein the first acquisition method comprises obtaining the first ofmeasurements while tripping out of the wellbore and the secondacquisition method comprises obtaining the second set of measurementswhile tripping into a wellbore.